1. Field of the Invention
The present invention concerns the incorporation of high melting point and/or hydrophobic products, notably endowed with significant biological activity, in compositions with a high water content.
More particularly, the invention relates to a stable homogeneous suspension, of high melting point and/or hydrophobic products, notably phytosterols, and to its application in the preparation of food compositions, such as dairy products.
2. Description of the Related Art
In fact, the improvement of the nutritional properties of products for food use, can lead to the incorporation of small quantities of ingredients with a favourable effect on the metabolism; however, the organoleptic and microbiological characteristics of the products must be protected.
Amongst the substances with biological activity, phytosterols and their derivatives have particular significance because of their physiological and pharmacological properties; in fact, it has been shown that of these compounds certain ones have a hypocholesterolemic activity when they are absorbed in a regular manner. It has thus been advocated to prepare the sterols in an appropriate quantity to use them for nutritional ends, with a view to lowering the level of cholesterol in the bloodstream. These sterols are especially obtained from unsaponifiable elements resulting from the saponification of animal and vegetable fats and oils.
The two main approaches considered to date for the incorporation of phytosterols and their derivatives in food or pharmaceutical compositions necessitate the solubilisation of phytosterols and their derivatives in the lipidic phases of a high fat content environment, the level of fat however being higher than 20%, and/or the use of emulsifying agents.
Several publications have thus described the incorporation of these compounds into compositions with a high fat content.
International application WO92/19640 describes food products containing β-sitostanol esters and fat at a level higher than 50%.
The Japanese patent application no 2.299.548 describes a biscuit containing phytosterols and its manufacturing process, either by use of an oil enriched with β-sitosterol mixed with flour before mixing in the other ingredients, or by prior mixing of the phytosterols with egg white before the introduction of the other ingredients.
However, it would be preferable to incorporate them in foodstuffs with a reduced fat content and with recognised nutritional qualities, such as fermented or unfermented dairy products. Such an inclusion causes difficulties inherent to the physico-chemical characteristics of phytosterols and to constraints unique to these types of food products, generally classed as fresh products.
U.S. Pat. No. 3,085,939 describes pharmaceutical compositions containing sitosterol which are stabilised by the presence of emulsifiers and a colloid material avoiding contact between the sitosterol and oil.
U.S. Pat. No. 4,195,084 describes pharmaceutical compositions containing sitosterols whose taste and stability are made acceptable by the combined presence of a chelating agent, carboxymethyl-cellulose, sorbitol, emulsifier and simethicone.
Resorting to such additives is unacceptable in products for food use, consumed in large quantities by healthy subjects.
However, as mentioned above, the incorporation of high melting point and/or hydrophobic substances, in finished dairy products with a high water content and low fat content, whilst preserving their properties, without resorting to these additives causes technical problems which to date have not been resolved.
In fact, it is not currently possible to incorporate hydrophobic substances with a high melting point at the beginning of the manufacturing process of a dairy product with a high water content and a low fat content. On one hand, their hydrophobic nature prevents them from dissolving in the initial essentially aqueous mixture, and, on the other hand, their melting point is higher than the temperature generally encountered in the preparation processes of dairy products and does not allow them to melt. A problem of heterogeneous distribution in the dairy product in question then has to be confronted.
Furthermore, these hydrophobic substances with a high melting point are generally presented in the form of a powder with large granulometry. Their inclusion, at the end of the preparation process of the dairy product with high water content and low fat content, therefore cannot be envisaged, as it would lead to a gritty sensation in the mouth due to the size of the powder particles. In addition, problems of microbiological contamination risk being confronted.